Submitted to: Journal of Kansas Entomological Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/23/2011
Publication Date: 11/7/2011
Citation: Landolt, P.J., Roberts, D., Corp, M., Rondon, S.I. 2011. Trap response of Dargida terrapictalis (Buckett)(Lepidoptera: Noctuidae) to a sex attractant in wheat-growing areas of Eastern Washington and neighboring Oregon. Journal of Kansas Entomological Society. 84(2):139-147. Interpretive Summary: Cutworms, armyworms, and loopers are caterpillars that damage numerous crops when they feed on foliage, fruits, stems, and roots. Growers need better information on those species that should be of concern on different crops, so that the pests can be detected and monitored for effective pest management. Researchers at the USDA, ARS Yakima Agricultural Research Laboratory, Wapato, WA, in collaboration with scientists at Oregon State University and Washington State University, are determining the identity of moth caterpillars that cause significant damage to crops in the Pacific Northwest and are developing methods for monitoring their abundance. Trapping experiments showed that the moth Dargida terrapictalis was abundant where damage to wheat had been blamed on the wheat head armyworm, Dargida diffusa. A sex attractant was demonstrated for both of these species of armyworm. This new information clarifies the identity of the insects causing damage to the crop and provides growers and pest managers with monitoring methods.
Technical Abstract: Traps in eastern Washington and northeast Oregon wheat fields, baited with a sex attractant for the moth of the wheat head armyworm Dargida diffusa (Walker), captured the congener moth Dargida terrapictalis (Bueckett). When the two components of a sex attractant for the wheat head armyworm were tested singly versus together in a trap, nearly all D. terrapictalis captured were in traps baited with the combination of (Z)-11-hexadecenyl acetate and (Z)-11-hexadecenal, indicating synergy of the two compounds as attractants. Traps baited with this sex attractant and maintained through the growing season captured D. terrapictalis primarily in May in Uatilla County, Oregon, and in June and early July in eastern Washington. Small numbers of D. diffusa were present also in these traps, largely coincident in time with D. terrapictalis captured. This is the first demonstration of a sex attractant for D. terrapictalis and confirms the presence of D. diffusa in the states of Oregon and Washington through the identification of trapped moths.